There's a reckoning among companies that built themselves up around Apple

Bank, tech stocks pull European shares down

As a result of the note, shares of Dialog Semiconductor PLC plunged to its lowest point in 16 years, as it became the second company recently to suffer from over-reliance on business from Apple.

Apple (AAPL) is unlikely to develop its own radio frequency chips for iPhones, making it less likely Broadcom (AVGO), Qorvo (QRVO), or Skyworks Solutions (SWKS) could be displaced by the iPhone maker, says a Pacific Crest Securities analyst. One source claimed Apple is hiring away Dialog Semiconductor's top engineers saying, "They are poaching like insane".

Apple has said that they plan to design their own graphics card for use in the iPhone, but the company may also be planning to internalize other aspects of the iPhone's development.

Apple's custom engineering saw it launch 64-bit chips ahead of the competition and its current mobile chips mean that the iPhone and iPad outstrip all of the Android competitors in most performance benchmarks.

However, things might change in 2018 when it decides to move power management chip design in-house as well. It makes sense for Apple to invest more in that area and replace the current parts with custom integrated designs. Dialog replaces numerous discrete power administration spares with one exceedingly incorporated gadget, empowering our users to create lighter and thinner convenient applications with higher power effectiveness bringing about longer battery life. A spokesperson declined to comment.

The downside of having Apple as a customer is that smaller suppliers can become dependent on its business due to the huge sales volumes generated by new iPhone contracts.

"I'm describing in the note that from 2019 onwards this could have a significant impact on earnings", Iltgen said, adding that there's a lot of uncertainty around the exact numbers because it will all depend on how much Apple is going to produce internally. About 80 engineers are already working on the Power Management chip.

As the revelation broke, a statement from Imagination claimed Apple would be working on its own graphics chip for use in future iPhones and iPads, and now it seems the company could be doing the same with battery tech.

The power management chip in the iPhone 5 was awful. The news sent Imagination's shares down 62 percent on April 3.